Characterisation of macular superficial vessel density alteration in preclinical ethambutol-induced optic neuropathy using optical coherence tomography angiography

Abstract

AimTo investigate the changes in macular vessel density (mVD) and its relationship to macular ganglion cell–inner plexiform layer (mGCIPL) thickness in patients receiving ethambutol (EMB) therapy for tuberculosis without recognisable clinical symptoms or signs of EMB-induced optic neuropathy (EON).MethodsA total of 23 eyes of 13 patients using EMB therapy for 6 months without EON (preclinical EON) as the EMB group, 40 eyes of 23 healthy individuals as the normal control group and 18 eyes of 10 patients with tuberculosis before receiving EMB therapy as the blank control group were retrospectively analysed. The mean peripapillary retinal nerve fibre layer (pRNFL) and mGCIPL thicknesses and mVD were measured using optical coherence tomography angiography. Patients in the EMB group were compared with individuals in the normal and blank control groups, and changes in macular parameters were evaluated.ResultsCentral circle mVD (cCVD) was significantly lower in the EMB group than in both control groups (generalised estimating equation (GEE), p=0.003 and 0.029, respectively). The mGCIPL thickness in all regions and the mean pRNFL thickness were not significantly different between the EMB group and both control groups (GEE, p=1.000 for all). There were no significant differences in mVD, mGCIPL thickness and mean pRNFL thickness between the normal control and blank control groups (p>0.05). In the generalised linear model analyses, the minimum and inferonasal mGCIPL thicknesses were positively correlated with cCVD in the EMB group (β=1.285, p=0.003 and β=0.770, p=0.024, respectively).ConclusionscCVD decreased with no changes in mGCIPL and mean pRNFL thicknesses in patients with preclinical EON. The minimum and inferonasal mGCIPL thicknesses were positively correlated with cCVD. cCVD might be an early indicator for monitoring early-stage EMB toxicity.

Macular Vessel Density in Diabetic Retinopathy Patients: How Can We Accurately Measure and What Can It Tell Us?

“…Macular vessel area density has been shown to decrease with age but can also act as a surrogate for macular perfusion and can be used to quantitatively monitor the effects of ophthalmological disorders on the vasculature. 26 For example, reduced macular vessel area density has been shown in patients with mild to moderate primary open-angle glaucoma, early-stage ethambutol induced optic neuropathy, and DR. 27 , 28 This metric along with vessel skeletonized/length density has also been shown to be highly reproducible in both healthy eyes and eyes with retinal disorders. 21 , 29 …”

Intraocular vascular analysis using optical coherence tomography angiography in patients with vascular paralytic strabismus

“…Meanwhile, since 2014, optical coherence tomography angiography (OCTA), which is advantageous because of its non-invasive and timesaving nature, has been used to detect retinal vasculature in vivo, such as in retinal artery and vein occlusion, diabetic retinopathy, and age-related macular degeneration [7,8]. Subsequently, the application of OCTA has been expanded, and it has been used to evaluate vessel analysis in various intraocular diseases, such as anterior segment ischemia, acute angle closure, and other optic neuropathies [9][10][11].…”